Automatic pressure-retaining valve for air-brake systems.



PATENTBD JULY 28, 1908.

J11). NIGHOL.

AUTOMATIC-PRESSURE RETAINING VALVE FOB. AIR BRAKE SYSTEMS.

APPLICATION FILED AUG. 15, 1907.

JAMES D. NIOHOL, OF FINLEY, WASHINGTON.

AUTOMATIC PRESSURE-RETAINING VALVE FOR AIR-BRAKE SYSTEMS.

Specification of Letters Patent.

Patented July 28, 1908.

Application filed. August 15,1907. Serial No. 388,703.

To all whom it may concern:

Be it known that 1, JAMES D. NICHOL, a citizen of the United States, residing at Finley, in the county of Benton and State of Washington, have invented new anduseful Improvements in Automatic Pressure-Retaining Valves for Air Brake Systems, of which the following is a specification.

This invention relates to air brake systems for trains, and more particularly to automatic pressure retaining valves.

The principal object of the invention is the rovision of a pressure-retaining device for brake mechanisms whereby the engineer of a train is capable of controlling the operation of the pressure-retaining valves on the cars simply by the ordinary brake valve in the cab of the engine which controls the train pipe pressure, thus relieving the train hands rom the necessity of manually o erating the pressure retaining valves in I t e ordinary manner with the accompanying advantage of quickness of operation and eliminating the danger to the trainman in passing from one car to another to operate the valves according to the resent method.

A further 0 ject is the provision of an automatically actuated pressure retaining valve so designed that the pressure in the train pipe normally maintains the valve 0 en and which is brought into operation when the train pipe pressure is reduced for setting the brakes.

Another object of the invention is the provision of a device of the character referred 'to including a weighted pressure-retaining valve and a spring-pressed piston or other suitable motor that is subjected to train pipe pressure for holding the valve in open position, there being a lost motion connection between the motor and valve for permitting the latter to operate automatically under the ressure in the brake cylinder in a well nown manner.

With these objects in view and others, as

will appear as the description proceeds, the

retaining valve in full and partial open po- SIl'ilOIIS.

Similar reference characters are employed to designate corresponding parts throughout the several views.

Referring to the drawing, A designates a casing composed of two hollow sections 1 and 2 that are cast or otherwise suitably constructed and of any a proved form, the sections being detachably connected by threads 3i The chamber 4 formed by the two sections contains a Weight 6 and a piston 7, which latter works in the upper end of the chamber which is preferably cylindrical at 8 to correspond Wit the piston, and on the section 1 is an internal annular shoulder 9 on which the piston 7 is adapted to rest. The section 1 of the casing A is provided with a tubular extension or neck 10 that has pro- Vision, such as threads 11, for connection With a pipe 12 leading to the brake cylinder of the air brake apparatus of the car. In the tubular portion 10 of the casing A is a ressure-retaining valve 13 in the form of a ollow piston closed at its upper end and open at its bottom end to receive the pressure from the brake cylinder, there being arranged in the wall of the piston valve 13, one or more triangular ports 14 that are adapted to be brought into register with exhaust ports or outlets 15 in the tubular portion 10. The upper closed end of the piston valve 13 is rigidly connected to the bottom of the weight y a stem 16 that passes through a bushing 17, the stern being non-circular, as is also the opening 18 of the bushing for the purpose of preventing the pressure-retaining valve from turning and thus maintain the ports 14 and 15 in alining relation. The piston valve 13 is provided with a suitable packing ring 19 for preventing the escape of pressure around the valve, but to insure against the accumulation of pressure on the top side of the valve, a vent 20 is provided in the wall of the casing A. The section 2 of the casing has a tubular extension 21 in which is disposed a helical compression spring 22 of suitable strength that serves to weight the piston 7 and whose tension is adjusted by an adjustable abutment 23 having threaded engagement in the upper end of the extension 21, whereby the piston can be weighted'to suit the train pipe pressure. The regulating spring 22 is so adjusted as to exert a pressure sufficiently less than-normal train pipe pressure that when the train pipe pressure is established on the underside of the piston, the combined weights of the piston 7, weight 6, and valve 13, and compression of spring 22 will be overcome and the 5 piston immediately raised and maintained in such position. In other words, the adjustment of the spring is such that the full train pipe pressure can operate the parts under normal working conditions for insuring the full release of the valve 13 immediately upon restoration of the train pipe pressure. The said abutment 23 has a non-circular head 24 for ermitting engagement by a wrench and app ied over the abutment and threaded on the extension 21 is a ca 25. On the top side of the piston 7 is a cy indrical boss 26 that has a working fit in the lower end of the bore of the extension 21 so as to constitute a guide for the piston, and the spring 22 bears at its'lower end on the said boss. The casing A is provided with an inlet opening 27 that communicates with the chamber 4 at a point below the piston 7 and this opening is adapted to be connected by a pipe 28 with the train pipe on the car so that the piston can be placed under the control of the engineers brake valve of the air brake system. The piston 7 is provided with a packing ring 29 for preventing the leakage of air to the top side of the piston, although a vent 30 is made in the section 2 to prevent pressure from accumulating above the piston in the event of-leakage around the latter.

Between the piston 7 and weight 6 is a lost motion connection, whereby the weight and pressure-retaining valve is permitted to have a limited movement independently of the piston, and in the present instance this connection consists of a stem 31 on the bottom side of the piston that has a head 32 freely movable in a socket 33 in the top side of the weight, there being a plate or other suitable retaining device 34 on the top side of the weight which is engaged by the head 32 when the weight is lifted by the piston 7.

The operation of the device may be briefly described as follows. As long as the train ipe pressure is maintained, the piston 7 will e he d in fully raised position, thereby sup porting the weight 6 and holding the pressure-retaining valve 13 out of service, the port 14 being registered with the port 15, as shown in Fig. 2, so that there will be no pressure in the brake cylinder. As soon as the train pipe pressure is reduced by the engineer manipulating the brake valve, the piston will drop under the influence of the spring 22 and thereby permit the weight 6 to move the valve 3 to the position shown in Fig. 1. Upon release of the brakes, the exhaust from the brake cylinder passes through the extension and acts on the retaining valve 13 so as to raise the latter against the' influence of the weight 6 to a position approximating 5 that shown in Fig. 3, to thereby permit the the retaining valve to lower the latter and I prevent any further escape of air. \Vhen the ressure is a a n restored in the tram pipe, the piston 7 Wlll be immediately raised and carry with it the weight 6 and valve 13 to cause the latter to occupy the position shown in Fig. 2, and thereby connect the brake cylinder with the atmosphere.

From the foregoing description, taken. in connection with the accompanying drawing, the advantages of the construction and of the method of operation will be readily apparent to those skilled in the art to which the invention appertains, and while I have described the principle of operation of the invention, together with the apparatus which I now consider to be the best embodiment thereof, I desire to have it understood that the apparatus shown is merely illustrative and that such changes may be made when desired, as are within the scope of the claims.

Having thus described the invention, what I claim is 2- 1. In an air brake apparatus, the co1nbination of a casing, a pressure retaining valve therein, a weight connected with the valve, a piston proportioned to permit normal train pipe pressure to lift the valve and weight, and a connection between the piston, and means for permitting the valve to be raised to partially open position by the pressure from the brake cylinder when the train pipe pressure is reduced.

2. In an air brake apparatus, the combination of a pressure-retaining valve, a fluid pressure motor under the control of train pipe pressure, and a connection between the motor and valve for permitting the latter to move independently.

3. In an air brake apparatus, the combination of a weighted pressure-retaining valve, a device controlled by the train pipe pressure, a lost motion connection between the device and valve for moving the valve by the device and for permitting the valve to move independently of the device for releasing pressure in a brake cylinder.

4. In a device of the class described, the combination of a casing, a piston therein, means for subjecting the piston to train pipe pressure, a pressure-retaining valve, and a connection between the piston and. valve.

5. In a device of the class described, the combination of a casing, a weighted piston, therein, means for subjecting the piston to fluid pressure, a weight in the casing, a lost motion connection between the weight and piston, and a pressure reducing valve connected with the weight.

6. In a device of the class described, the combination of a two-part casing provided with tubular extensions, an exhaust port in one of the extensions, a piston valve in the said extension having a port adapted to register with the exhaust port, means for yieldingly holding the valve in one position, and automatic means for actuating the valve in opposition to the said means, said automatic means being housed within said casing.

7. In a device of the class described, the combination of a casing, a piston therein, an adjustable sprin weighting the piston, means for admitting fluid under pressure to the casing to act on the piston, a weight in the casing, means for connecting the piston and weight together, and a pressure-retaining valve connected with the weight.

8. In a device of the class described, the

combination of a casing provided with an exhaust ort, a pressure-retaining valve in the form 0 a piston 1provided with a port adapted to register wit that of the casing, a means in the casing tending to hold the valve with its port out of register with that of the easing, a piston in the casing, a lost motion connection between the piston and device, means for subjecting the piston to fluid pressure to move the same for bringing the ports into register, and means for returning the piston when the said fluid pressure is removed.

In testimony whereof I affix my signature in presence of two Witnesses.

- JAMES D. NICHOL. Witnesses:

Enw. E. HOPE, S. L. FORBES. 

